I have just now checked your shader in Unity here, smoke_th, and since it has full support for a proper 2x1 pixel-ratio format that is quite perfectly needed for this game jam, you are *definitely* allowed to use it for your own game project!! ;)
The only thing is, be sure to select the mode “64Commanders” and click in a checkmark right next to “Apply Resolution” and you are all good and set! ^^
With all that said, smoke_th, I wish you the truly best of success on creating your game project for my game jam here!! Let’s rock!!! ^-^=b !!
Well i mean it is a bit more advanced than this - i can use any downscaler res (with any pixel ratio) and any palette you provided. note - you can buy it on unity store or here on itch.io, and it's only 2 dollaz